Starship test flight largely successful

The SpaceX spaceship, the largest rocket in the world, has successfully completed its first test flight. On 14 March at 14:25 Central European Time, the 120-metre-high rocket, powered by liquid methane and liquid oxygen, lifted off from the launch pad with a super-heavy booster as the first stage and Starship as the second stage. After around three minutes of flight, the Starship separated from the first stage as planned in a "hot stage" manoeuvre. The second stage successfully switched off its engines at an altitude of around 150 kilometres and then reached its intended target altitude of 234 kilometres.

It opened and closed its cargo hatch - another scheduled test - before also returning to the atmosphere. Contact with the Starship was then lost upon entry. The largely successful flight is an important step forward for the rocket, which with its enormous thrust and large cargo capacity should one day make manned missions to the moon and perhaps even Mars possible.

In the run-up to the launch, SpaceX repeatedly emphasised that the flight was just a test. Although the hope was to carry out the flight according to the planned schedule, the main objective was to obtain as much data as possible. The two previous integrated flight tests had both ended prematurely after technical faults. This time, however, almost everything went smoothly. Only the planned ignition of the engine in flight failed, and contact with the super-heavy booster was lost when the second stage returned to Earth.

The Starship also appears to have lost some of its 18,000 heat tiles on its return to the atmosphere, which may have led to the loss of telemetry at an altitude of around 65 kilometres. The booster and Starship are designed to land vertically under their own power, which can significantly reduce launch costs. Like Starship, the booster was intended to test controlled descent into the atmosphere today, but not landing.

Successful flight on the third attempt

The third launch attempt of the world's largest rocket followed a slightly different plan to the first two tests. From the Starbase spaceport in Boca Chica, Texas, the rocket did not fly westwards towards Hawaii like its two predecessors, but south-eastwards over southern Africa. One question mark concerned the weather. The fog that shrouded the launch pad was less of a problem, but wind was also forecast. SpaceX put the chances of suitable launch conditions at 70 per cent. In addition, boats entered the exclusion zone around the launch pad, the company reported in the meantime. The launch was delayed by a total of around one and a half hours.

Compared to the last test, SpaceX has made a number of changes to the rocket, including to the fuelling system. The company also installed new equipment on the launch platform, which should reduce the refuelling time from 97 to 50 minutes. After take-off, the aircraft tested a number of processes, including transferring fuel between two tanks and opening and closing the Starship's cargo hatch

The successful flight of the first and second stage is a major success for SpaceX after the first two flight tests failed spectacularly. During the first joint launch attempt of the booster and Starship on 20 April 2023, three of the super-heavy booster's 33 Raptor rocket engines failed as soon as it took off. The rocket's exhaust jet destroyed the launch pad and hurled debris kilometres into the landscape. More engines went out in flight, the rocket began to tumble and exploded.

On 18 November 2023, another rocket took off for a second flight test from the reconstructed and improved launch pad in Boca Chica. This time, the engines worked during the ascent. However, after the separation of the first and second stage, engine problems caused the booster to explode. Despite a telemetry fault, the second stage reached an altitude of 150 kilometres before it was detonated in a controlled manner due to the technical fault.

It is currently unclear why contact with the Starship was lost on re-entry into the atmosphere. It is possible that the heat shield was damaged by vibrations during re-entry. Obtaining data on the behaviour of the second stage during this critical phase of the flight was also an important objective of the flight test. During further launches, SpaceX will now attempt to complete the return to the atmosphere and reach a stable orbit. Another booster and a Starship are currently being prepared for the next flight test; however, the launch date has not yet been set.

Spectrum of Science

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